Gun choke mounting apparatus



A ril 17, 1962 F. A. PACHMAYR 3,029,540

GUN CHOKE MOUNTING APPARATUS Filed July 25, 1960 2 Sheets-Sheet 1 FRANKA. ,Pna/Mn YR i 2 5 INVENTOR.

ATTO RNEYS April 17, 1962 F. A. PACHMAYR GUN CHOKE MOUNTING APPARATUS 2 Sheets-Sheet 2 Filed July 25, 1960 l 'kn/vK A. PHCHMH YA INVENTOR.

BY V LII/1 ATTOFZN EYS Nm mm mm vw Nu QIJIQ Nv mu v 7 ma vm r on .I s m. 3 2 2. MN

3,2954% Patented Apr. 17, 1962 3,029,540 GUN CHOKE MOUNTING APPARATUS Frank A. Pachmayr, Glendale, Calif. (1220 S. Grand Ave, Los Angeles, Calif.) Filed July 25, 1960, Ser. No. 45,057 11 Claims. (Cl. 42-79) This invention relates generally to what are known as gun chokes or muzzle devices, which are usable to control gun shot patterns by reason of the nature and degree of direction given the shot passing through the choke. More particularly, the invention is concerned with the problem of quickly mounting a gun choke on a barrel, it being the purpose of the invention to provide improved apparatus and methods for rigidly securing a gun choke on a barrel.

Heretofore, muzzle devices or chokes have been secured on gun barrels by soldering or brazing them in position,

vthis practice being found extremely time-consuming and expensive so that problems are presented, particularly in the field, where brazing and soldering equipment is not readily available. present invention makes possible the rapid attachment or securing of a muzzle device or choke to the end of the gun barrel, characterized in that such attachment may be completed very quickly and easily by anyone, including users who desire to attach chokes to gun barrels in' the field.

Referring first to the apparatus for accomplishing the above purpose, the invention broadly provides means on the gun barrel for exerting loading on a tubular choke housing into which the forward end of the gun barrel is receivable, such loading acting to produce gripping force transmission between the housing and barrel of such a nature that the housing is securely mounted on the barrel.

Reference herein to the tubular choke housing will be understood to mean the entire choke housing in the event it is made as a one-piece body, and also to the rear section of such a housing inthe event the entire housing is made up of forward and rearward sections, these normally being screwed together.

More specifically, the means on the barrel for exerting loading on the housing includes an insert Within the housing and a rotary tightener exposed at the rear of the housing, the tightener being operable to exert loading on the housing, acting to produce gripping force transmission through the insert and between the housing rearward extent and barrel. In addition, the insert and the choke housing are co-operable to support the housing on the barrel with the forward end of the housing directed forwardly in slightly angularly deviated relation of the length direction of the gun barrel. As a result, the choke housing may be quickly mounted on the barrel by following the steps that include positioning the tubular mounting means including the insert and rotary tightener over the forward end of the barrel, along with the rearward extent of the tubular choke housing, and then adjusting the positions of the tubular mounting means and the choke housing relative to the end of the barrel by simultaneously pulling rear'wardly on the housing and wedging the insert between the barrel and the housing bore. Accordingly, the insert is caused to exert loading on the choke housing acting to produce gripping force transmission between the housing and the barrel.

Additional steps include severing the barrel forward end in order to produce a barrel of correct length for mounting the choke housing, and adhesively bonding the insert to thebarrel, as will be described. Finally the bar rel end may be swaged or flared before of after the choke housing is securely mounted thereon to provide additional gripping strength.

As a solution to these problems, the 7 These and other objects and advantages of the invention, as well as the details of illustrative embodiments, will be further understood from the following detailed description of the drawings in which:

FIG. 1 is a view showing a side elevation of choke housing secured to the gun barrel, as by the mounting means disclosed;

FIG. 2 is an exploded perspective showing all of the elements of the mounting means and also of the choke housing and barrel;

FIG. 3 is a side elevation of the barrel end after it has been severed, and adhesive bonding material has-been applied thereto;

FIG. 4 is a side elevation in section showing the barrel choke housing and mounting means in disconnected condition;

FIG. 5 is a view like FIG. 4, except that the mounting means is located on the barrel end prior to placement of the choke housing thereon;

FIG. 6 is a view like FIG. 1, excepting that the barrel swaging tool is shown inserted in the barrel end just prior to the swaging operation;

FIG. 7 is a view like FIG. 4, but showing an alternative form of the invention; 1

FIG. 8 is a view like FIG. 1, but showing a modification of the invention; and,

FIG. 9 is a section taken through the modified collar of FIG. 8.

Referring first to FIGS. 1 through 3, the shotgun barrel forward end is shown at 10 with adhesive bonding material applied to the barrel exterior, as seen at 11. The adhesive may consist of any suitable metal-to-metal bonding material which is applied cold to the barrel. One typical adhesive has the trade name Lefkoweld #108, comprising an epoxy type resin manufactured by Leffingwell Chemical Co., Whittier, California. The forward and rearward sections of a tubular choke housing 12 are indicated at 13 and 14, these being screwed together as by the pin and box threaded connection shown at 15, which is typically made up after the rear section '14 has been securely mounted on the barrel forward end.

In accordance with the invention, means is provided on the barrel for exerting loading on the housing 12, and specifically section 14 thereof, acting to produce gripping force transmission between the housing and barrel, whereby the housing may be securely mounted on the barrel. As shown in FIGURES l and 2, such means typically takes the formof an insert 16 on the barrel and within the housing, and a rotary tightener 17 on the barrel and exposed at the rear of the housing. The insert 16 typically comprises an annular collar containing a lengthwise split 18, the collar having a cylindrical bore 19 and a frusto-conical forwardly tapering outer surface or shoulder 20, the collar being sized for endwise reception on the barrel.

The rotary tightener '17 is shown in the form of a nut having an externally threaded shank 21 adapted to screw into the internally threaded box portion 22 of the housing section 14. A flange 23 on the nut is exposed at the rear of section 14 to be manually rotated for turning the nut, thereby advancing it forwardly relative to section 14 in order that the shoulder 24 at the forward end of the shank 21 may engage and advance the collar 16 forwardly relative to the section 14.

The latter has a forwardly tapering bore or shoulder .25 adapted to seat the shoulder 20 of the collar during 3 choke housing section 14 and the barrel, whereby the housing is securely mounted on the barrel. In this connection, it will be observed that sufficient clearance or relief is provided at 26 between the nut shank 21 and the barrel it} as to accommodate angular misalignment of the nut during tightening thereof into the housing.

It is clear from FIG. .1 that the choke housing :12 is slightly deviated upwardly in forward directional extent, this being in accordance with desired action of the housing to direct the shot pattern forwardly of the gun barrel. FIG. 4 shows the manner in which such slight angular upward deviation of the choke housing may be obtained with accuracy during the mounting process. As illustrated, the collar 16 has its forwardly tapering outer surface 20 centered about an axis 28, which extends forwardly at a slight upward angle with respect to the axis 29 of the gun barrel. This is further illustrated by the upwardly spaced location relative to the axis 29' of the apex 3d of the conical locus defined by the collar surface 20. In other words, the surface 26 is slightly eccentric with respect to the axis 29, and it will be understood that in the form of the invention shown in FIG. 4 the frustoconical bore 25 of the choke housing section 14 may be concentric or centered about the forward axis of the housing, which coincides with the axis 23.

Referring now to the steps involved in mounting the housing section 14 on the gun barrel, it is found desirable in practice to cut the gun barrel off to proper length and to face off or square the end of the barrel shown at 31 in FIG. 3. Thereafter, any burrs that might be left are removed, especially on the inside diameter. The outer surface of the barrel is then prepared for bonding as by roughening that surface near the end of the barrel, such roughening being typically accomplished by sanding or scoring the barrel end portion to which the adhesive bonding material is to be applied.

The end of the barrel and the tapered collar 16 are then thoroughly cleaned, as for example with cleaning fluid such as naptha trichloroethylene or metholethylketone. Thereafter, the nut 17 and the tapered collar 16 are placed in that order over the end of the barrel, so as to leave exposed the end portion of the barrel to which the layer of fluid adhesive is then applied, as indicated at 11 in FIG. 3. The collar 16 may then be moved over onto the adhesive in forwardly spaced relation to the nut 17, and the housing section 14 is then installed in place over the end of the barrel allowing the shoulder 32 of the housing to seat against the barrel terminal end face 31, as better seen in FIG. 6.

During such installation, the top of the housing 14 indicated by the bead 33 is aligned with the top of the gun barrel and the eccentric collar 16 is properly oriented with respect to the housing 14 by causing the collar split 18 to receive the lower end 34 of a pin 35 mounting and bead 33. In this condition of alignment, the housing is connected onto the barrel by rotatably tightening the nut 17 into the housing rearward end, until the nut forward shoulder 24 presses forwardly and urges the split collar 16 into tight wedging interengagement with the barrel 19 and the tapered bore 25 of the housing 14. The tighter the nut connection with the housing, the tighter the gripping force is developed between the housing collar and the barrel which force is transmitted by the insert or collar 16.

Thereafter, the barrel and the installed housing and mounting means is placed in an oven at elevated temperature, for example 250 PI, for sufficient time to cure the adhesive bond, asfor example 45 minutes. Additional connection strength may be developed by swaging the barrel end before the baking step. FIG. 6 shows a swaging tool 36 in the form of a mandrel having a pilot end portion 37 and a tapered land 38 between the pilot portion 37 and the main body portion 39 of the mandrel or tool. As the latter is advanced relatively rearwardly into the bor 40 of the housing 14, the land 38 comes into interference engagement with the barrel forward end at 4'1, and further rearward movement of the swaging tool effects outward flanging or swaging of the barrel forward end into an annular recess 42 sunk outwardly into the bore of the housing 14. The installation of the nut collar and housing onto the barrel forward end and the swaging operation may all be carried out while the barrel is held in or by a split holding fixture generally indicated at 43 in FIG. 5.

In the modified form of the invention shown in FIG. 7, the modified collar 44 has a bore 45 conforming generally to the cylindrical configuration of the gun barrel It on which the collar is to be placed while it is held in the choke housing rearward section 46. The collar exterior surface 47 is forwardly tapered and is concentric about the axis 48 of the gun barrel. The upper angular deviation of the housing 46 relative to the axis 48 is obtained by forming the tapered bore 49 of the housing to be concentric about the axis 50, which has the deviation desired, the annular taper 49 thus being properly oriented eccentrically with respect to axis 43 when the collar 44 is inserted into the tapered bore 49 of the housing 46 and this assembly is then placed on the barrel forward end. Also, when the nut 17 is connected into and with the housing 46, the latter will have the proper upward angular deviation relative to the axis 423.

The nut 17 shown in the drawings may pivot relative to the barrel due to the provision of the clearance 26 previously mentioned, and also by virtue of the provision of annular pivot or bearing 51 at the rearward end of the nut and adjacent barrel lit. Accordingly, a tight interconnection between the nut and the housing is facilitated by virtue of the ability of the nut to pivot.

In the modified form of the invention shown in FIGS. 8 and 9, the modified insert 56 is in the form of a cylindrical collar containing a lengthwise split 57 accommodating tight wedging of the collar between the housing 58 and barrel 59 in response to forward and rotary ad vancement of the forward threaded extent 60 of nut tightener 61 into the housing. The collar and housing have interengaged forwardly tapering shoulders 62 and 63 at the forward terminal of the collar. Also, the collar and tightenerextent 66 have interengaged rearwardly tapering shoulders 64 and 65 at the rearward end of the collar. The lower end 66 of pin 67 projects into the split 57 to orient the collar and its end shoulders relative to the barrel and housing, and one or more of the shoulders 62 through 65 may be so formed as to cause the axis of the housing to deviate upwardly slightly in a forward direction, relative to the barrel axis, and to predetermined extent for shot directing purposes.

I claim:

1. For combination with a generally forwardly extending gun barrel, a generally forwardly extending tubular choke housing into which the forward end of the gun barrel is receivable, and means on the barrel for exerting loading on the housing acting to produce gripping force transmission between the housing and barrel, whereby the housing may be securely mounted on the barrel, said means including an externally threaded nut pivotally mounted on the barrel and having threaded interconnection with the housing.

2. The invention as defined in claim 1, in which said means has body extent within said housing supporting said housing with the forward end thereof directed forwardly in slightly angularly deviated relation to the length direction of the gun barrel.

3. The invention, as defined in claim 1, in which said means and housing are adjustably interconnected so that said gripping force transmission 1-;ay be varied.

4. In combination with a generally forwardly and axially extending gun barrel, a generally forwardly extending tubular choke housing having rearward extent into which the forward end of the gun barrel is received, and means on the barrel including an insert within said housing and 5 a rotary tightener exposed at the rear of said housing for exerting axially oppositely directed loading on the housing and insert acting to produce gripping force transmission through said insert and between the housing rearward extent and barrel, whereby the housing may be securely mounted on the barrel, said housing and insert having interengaged wedge shoulders through which said gripping force is transmitted, said tightener and housing having interengaged screw threads out of the path of said gripping force transmission.

5. The invention as defined in claim 4, in which said tightener comprises a nut rotatable about the barrel and pivotally mounted thereon.

6. The invention, as defined in claim 5, in which said innsert supports the housing with the forward open end thereof directed forwardly in slightly an-gularly deviated relation to the gun barrel length direction.

7. The invention, as defined in claim 6, in which said tapered shoulders are frusto-conical, at least one of said tapered shoulders being eccentric with respect to the gun barrel axis.

8. The invention, as defined in claim 4, in which said insert comprises a collar extending about the barrel and containing a split accommodating tight wedging of the collar between the housing and the barrel in response to said one-way rotation of said tightener.

housing has a rearwardly facing internal shoulder engageable with the terminal end of the barrel for limiting rearward movement of the housing on the barrel.

11. The invention, as defined in claim 4, in which said means includes a swaged flange on the barrel forwardly of said insert for preventing forward removal of the insert off the barrel.

References Cited in the file of this patent UNITED STATES PATENTS 1,659,268 Hooley Feb. 14, 1928 2,167,173 Fleming July 25, 1939 2,249,899 Hogg July 22, 1941 2,453,747 Egleson Nov. 16,1948 2,484,988 Finlay Oct. 18, 1949 2,527,988 Dillon Oct. 31, 1950 2,641,822 Sampson June 16, 1953 2,712,193 Mathis July 5, 1955 FOREIGN PATENTS 5,692 7 France Mar. 28, 1906 

